Apparatus for transmitting sound-waves.



F. H. BROWN. APPARATUS FOB. TRANSMITTING SOUND WAVES. Anmoulon rump APR.17, 1907.

1,006,429, Patented Oct. 1:7, 1911;

Lined? fnven imi' 6. Q I f UNITED STATES PATENT OFFICE.

FRED HARVEY BROWN, OF LOS ANGELES, CALIFORNIA, ASSIGNOR TO NATIONAL ELECTRIC & MAGNETIC COMPANY.

APPARATUS FOR TRANSMITTING SOUND-WAVES.

Specification of Letters ZPatent.

Application filed April 17, 1907.

Serial N 0. 368,761.

To all whom it may concern:

Be it known that I, FRED HARVEY BROWN, of Los Angeles, California, (whose address is now 308 Slaughter Building, Dallas, Texas,) have invented a new apparatus for transmitting sound-waves, such as articulate speech or singing, musical sounds, and

harmonics, as well as telegraphic and tele phonic articulations, to a distant point by magnetic induction; and I do declare the following is a full and clear description of the invention and one form of a device which will enable others skilled in the art to apply my apparatus.

The object of the invention is to transmit electrical and magnetic impulses, whose periods of vibrations are synchronous and in harmony with musical, telephonic, harmonic and the articulated vibrations of telegraphy.

Another object of my invention is to furnish an apparatus l v 'i-ich these different vibrations can be heard, at the receiving end.

Another object of this invention is to furnish a device by which the before described objects may be carried out without the necessity of using a continuous metallic conductor throughout a circuit, but to attain these objects by transforming the generating currents into electric and magnetic waves, which will pass through an intervening atmosphere or other media and synchronously reproduce in proper receiving instruments, the various electrical and magnetic potentials created at the transmitting end.

In carrying out my invention I cause the potential of a continuouscurrent to be varied as the current passes through a microphonic or other suitable variable contact in direct or contiguous contact with a musical. or any sound-producing generator, as the human voice, and to interrupt rhythmically, and harmonically the vibrations of the human voice or other sounds, by thus varying the continuity of a current flowing through said variable contact.

I accomplish the results desired, in part, by causing this varying current to pass through a coil of thoroughly insulated wire of large diameter and a large number of convolutions, the said coilbeing in closed circuit with the transmitting devices. This large insulated coil throws off in the surrounding atmosphere magnetic waves, which are accentuated by the static inductive capacity of the insulation of the coil. Also in part at the receiving end, by erecting a sim-' ilar coil as described, at a distant point, the winding of this coil having in circuit therewith a telephone receiver, a polarized relay,

or other suitable recordin or receiving de-' vice. The planes of the windings of each of these two large coils must be parallel with each other.

Having described the objects of my invention, I 'will now describe the details of its working, and some of the devices by which it can be carried into practical use.

The reference letters and figures in the specification refer to similar letters and figures in the drawings.

In the drawings I show a condenser E superimposed on the coil and battery circuit. The condenser acts as a kind of equalizer in storing up and giving out the superfluous current, but outside of this effect the device will work as well without the condenser as with ,it. I prefer the extradirect impulses in this art as the output and resulting inductive effect to a distance is very much greater than a direct or alternating current. After showing this application of this invention, it can readily be seen that it can be applied to many utilitarian industries such as signaling to and from trains, etc. In such instances the large coil traverses the whole division of the road near the tracks. A few convolutions of large wire on each side of the track is suspended on poles. Conductor on train can talk into a small coil suspended inside the roof of the car transmitter and batteries in circuit with its windings creating magnetic waves in the coil. In the car these waves will pass into the larger wire placed on each side of the track throughout its length into the train number ofreceiving coils B each with its Patented Oct. 17, 1911. p

3 receiver 7) in series with its windings may be increased to quite a large number thereof without seeming to diminish the volume of the sounds taken up by each of them from the transmitting coil A.

In the figure the transmitting coil as "shown onleft of drawing consists of the large transforming coil A which transforms the varying electrical impulses into magnet1c waves of the same variations. The

,coil I transforms the'battery current into extradirect impulses.

circuits.

- G is the iron core of the said coil.

E is a condenser which may be used or not as verylittle variation is observed in its application although it tendsto act as an equalizer of the current by storing the same during its variations.

d d are the points of contact of the several b is the battery which energizes the coils. I is the microphone by which the current is varied in harmony with sound waves.

In practice when the transmitter b is talked into or music is played contiguous thereto, the coilIwill have the continuity of 'its currentand also the magnetic stress of "its iron-core G varied, and also the extra- .0 transformed into magnetic waves also in direct electrical impulses in the transmitting coil ..A varied in *harmony therewith and synchronism therewith and radiate outward in. space until-these radiations reach a similarly arranged. station at a distant point whcn these waves take residence in the coil .or'colls at the receiving station, this being transformed into electrical impulses and in '-with the transmitting coil as described by the receiver in series therewith made audible in theshape of sound waves therewith.

I'do not wish to confine myself to what is shown in the drawings and the exact description as shown and described as it is evident that any one skilled in the art can change the relative position of the receiving coil and its receiver by placing it in series me and make many other changes in-the relative relation of parts without departing from the spirit or claims or economic results of my invention.

Having described my process and various devices for carrying it into practice what I claim as my invention is:

1. An apparatus for reproducing sound waves magnetically to a distant point in a wireless manner, which consists of a source of electrical generation in series with a circuit for direct currents; a circuit for extra direct currents superimposed thereon-said superimposed circuit forming part of the t-ions and large diameter, said coil being adapted to transform electrical impulses into magnetic waves, a microphone in series with the windings of the first or primary coil and source of electrical generation, a receiving coil of large diameter at a distant point having many convolutions, a telephone cuit superimposed on the windings of said coil, a magnetic Wave transforming coil in series with the line circuit comprising a transmitting station, in combination with a similar or suitable set and arrangement of devices 'at a distant point comprising a receiving coil having a telephone receiver in series with its windings at a distant point from the transmitting station, as shown and described for the purpose, as set forth.

FRED HARVEY BROWN.-

Witnesses:

D. M. BROWN, G. F. BROWN.

e0 winding of a large coil of many convolu-' 

